New JWK_TO_PEM and PEM_TO_JWK functions

We have introduced two new functions:

• JWK_TO_PEM converts a JSON Web Key to Privacy Enhanced Mail (PEM) format

• PEM_TO_JWK converts a PEM-encoded key or X.509 certificate to JWK format

See the docs for JWK_TO_PEM and PEM_TO_JWK for more information.